MathUtils

java.lang.Object
- org.matheclipse.parser.client.math.MathUtils

```
public final class MathUtils
extends java.lang.Object
```
Some useful additions to the built-in functions in Math.

Version:

$Revision: 1.1 $ $Date: 2008-02-10 12:28:59 -0700 (Sun, 10 Feb 2008) $

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static int`	`addAndCheck(int x, int y)` Add two integers, checking for overflow.
`static long`	`addAndCheck(long a, long b)` Add two long integers, checking for overflow.
`static long`	`binomialCoefficient(int n, int k)` Returns an exact representation of the Binomial Coefficient, "`n choose k`", the number of `k`-element subsets that can be selected from an `n`-element set.
`static double`	`binomialCoefficientDouble(int n, int k)` Returns a `double` representation of the Binomial Coefficient, "`n choose k`", the number of `k`-element subsets that can be selected from an `n`-element set.
`static double`	`binomialCoefficientLog(int n, int k)` Returns the natural `log` of the Binomial Coefficient, "`n choose k`", the number of `k`-element subsets that can be selected from an `n`-element set.
`static double`	`cosh(double x)` Returns the hyperbolic cosine of x.
`static boolean`	`equals(double[] x, double[] y)` Returns true iff both arguments are null or have same dimensions and all their elements are `equals`
`static boolean`	`equals(double x, double y)` Returns true iff both arguments are NaN or neither is NaN and they are equal
`static long`	`factorial(int n)` Returns n!.
`static double`	`factorialDouble(int n)` Returns n!.
`static double`	`factorialLog(int n)` Returns the natural logarithm of n!.
`static int`	`gcd(int u, int v)` Gets the greatest common divisor of the absolute value of two numbers, using the "binary gcd" method which avoids division and modulo operations.
`static int`	`hash(double value)` Returns an integer hash code representing the given double value.
`static int`	`hash(double[] value)` Returns an integer hash code representing the given double array value.
`static byte`	`indicator(byte x)` For a byte value x, this method returns (byte)(+1) if x >= 0 and (byte)(-1) if x < 0.
`static double`	`indicator(double x)` For a double precision value x, this method returns +1.0 if x >= 0 and -1.0 if x < 0.
`static float`	`indicator(float x)` For a float value x, this method returns +1.0F if x >= 0 and -1.0F if x < 0.
`static int`	`indicator(int x)` For an int value x, this method returns +1 if x >= 0 and -1 if x < 0.
`static long`	`indicator(long x)` For a long value x, this method returns +1L if x >= 0 and -1L if x < 0.
`static short`	`indicator(short x)` For a short value x, this method returns (short)(+1) if x >= 0 and (short)(-1) if x < 0.
`static int`	`lcm(int a, int b)` Returns the least common multiple between two integer values.
`static double`	`log(double base, double x)` Returns the logarithm for base `b` of `x`.
`static int`	`mulAndCheck(int x, int y)` Multiply two integers, checking for overflow.
`static long`	`mulAndCheck(long a, long b)` Multiply two long integers, checking for overflow.
`static double`	`normalizeAngle(double a, double center)` Normalize an angle in a 2&pi wide interval around a center value.
`static byte`	`sign(byte x)` Returns the sign for byte value `x`.
`static double`	`sign(double x)` Returns the sign for double precision `x`.
`static float`	`sign(float x)` Returns the sign for float value `x`.
`static int`	`sign(int x)` Returns the sign for int value `x`.
`static long`	`sign(long x)` Returns the sign for long value `x`.
`static short`	`sign(short x)` Returns the sign for short value `x`.
`static double`	`sinh(double x)` Returns the hyperbolic sine of x.
`static int`	`subAndCheck(int x, int y)` Subtract two integers, checking for overflow.
`static long`	`subAndCheck(long a, long b)` Subtract two long integers, checking for overflow.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - addAndCheck
```
public static int addAndCheck(int x,
                              int y)
```
    Add two integers, checking for overflow.
    
    Parameters:
    
    x - an addend
    
    y - an addend
    
    Returns:
    
    the sum x+y
    
    Throws:
    
    MathException - if the result can not be represented as an int
    
    Since:
    
    1.1
  - addAndCheck
```
public static long addAndCheck(long a,
                               long b)
```
    Add two long integers, checking for overflow.
    
    Parameters:
    
    a - an addend
    
    b - an addend
    
    Returns:
    
    the sum a+b
    
    Throws:
    
    MathException - if the result can not be represented as an long
    
    Since:
    
    1.2
  - binomialCoefficient
```
public static long binomialCoefficient(int n,
                                       int k)
```
    Returns an exact representation of the Binomial Coefficient, "n choose k", the number of k-element subsets that can be selected from an n-element set.
    Preconditions:
    - 0 <= k <= n (otherwise IllegalArgumentException is thrown)
    - The result is small enough to fit into a long. The largest value of n for which all coefficients are < Long.MAX_VALUE is 66. If the computed value exceeds Long.MAX_VALUE an ArithMeticException is thrown.
    Parameters:
    
    n - the size of the set
    
    k - the size of the subsets to be counted
    
    Returns:
    
    n choose k
    
    Throws:
    
    java.lang.IllegalArgumentException - if preconditions are not met.
    
    MathException - if the result is too large to be represented by a long integer.
  - binomialCoefficientDouble
```
public static double binomialCoefficientDouble(int n,
                                               int k)
```
    Returns a double representation of the Binomial Coefficient, "n choose k", the number of k-element subsets that can be selected from an n-element set.
    Preconditions:
    - 0 <= k <= n (otherwise IllegalArgumentException is thrown)
    - The result is small enough to fit into a double. The largest value of n for which all coefficients are < Double.MAX_VALUE is 1029. If the computed value exceeds Double.MAX_VALUE, Double.POSITIVE_INFINITY is returned
    Parameters:
    
    n - the size of the set
    
    k - the size of the subsets to be counted
    
    Returns:
    
    n choose k
    
    Throws:
    
    java.lang.IllegalArgumentException - if preconditions are not met.
  - binomialCoefficientLog
```
public static double binomialCoefficientLog(int n,
                                            int k)
```
    Returns the natural log of the Binomial Coefficient, "n choose k", the number of k-element subsets that can be selected from an n-element set.
    Preconditions:
    - 0 <= k <= n (otherwise IllegalArgumentException is thrown)
    Parameters:
    
    n - the size of the set
    
    k - the size of the subsets to be counted
    
    Returns:
    
    n choose k
    
    Throws:
    
    java.lang.IllegalArgumentException - if preconditions are not met.
  - cosh
```
public static double cosh(double x)
```
    Returns the hyperbolic cosine of x.
    
    Parameters:
    
    x - double value for which to find the hyperbolic cosine
    
    Returns:
    
    hyperbolic cosine of x
  - equals
```
public static boolean equals(double x,
                             double y)
```
    Returns true iff both arguments are NaN or neither is NaN and they are equal
    
    Parameters:
    
    x - first value
    
    y - second value
    
    Returns:
    
    true if the values are equal or both are NaN
  - equals
```
public static boolean equals(double[] x,
                             double[] y)
```
    Returns true iff both arguments are null or have same dimensions and all their elements are equals
    
    Parameters:
    
    x - first array
    
    y - second array
    
    Returns:
    
    true if the values are both null or have same dimension and equal elements
    
    Since:
    
    1.2
  - factorial
```
public static long factorial(int n)
```
    Returns n!. Shorthand for n Factorial, the product of the numbers 1,...,n.
    Preconditions:
    - n >= 0 (otherwise IllegalArgumentException is thrown)
    - The result is small enough to fit into a long. The largest value of n for which n! < Long.MAX_VALUE is 20. If the computed value exceeds Long.MAX_VALUE an ArithMeticException is thrown.
    Parameters:
    
    n - argument
    
    Returns:
    
    n!
    
    Throws:
    
    MathException - if the result is too large to be represented by a long integer.
    
    java.lang.IllegalArgumentException - if n < 0
  - factorialDouble
```
public static double factorialDouble(int n)
```
    Returns n!. Shorthand for n Factorial, the product of the numbers 1,...,n as a double.
    Preconditions:
    - n >= 0 (otherwise IllegalArgumentException is thrown)
    - The result is small enough to fit into a double. The largest value of n for which n! < Double.MAX_VALUE is 170. If the computed value exceeds Double.MAX_VALUE, Double.POSITIVE_INFINITY is returned
    Parameters:
    
    n - argument
    
    Returns:
    
    n!
    
    Throws:
    
    java.lang.IllegalArgumentException - if n < 0
  - factorialLog
```
public static double factorialLog(int n)
```
    Returns the natural logarithm of n!.
    Preconditions:
    - n >= 0 (otherwise IllegalArgumentException is thrown)
    Parameters:
    
    n - argument
    
    Returns:
    
    n!
    
    Throws:
    
    java.lang.IllegalArgumentException - if preconditions are not met.
  - gcd
```
public static int gcd(int u,
                      int v)
```
    Gets the greatest common divisor of the absolute value of two numbers, using the "binary gcd" method which avoids division and modulo operations. See Knuth 4.5.2 algorithm B. This algorithm is due to Josef Stein (1961).
    
    Parameters:
    
    u - a non-zero number
    
    v - a non-zero number
    
    Returns:
    
    the greatest common divisor, never zero
    
    Since:
    
    1.1
  - hash
```
public static int hash(double value)
```
    Returns an integer hash code representing the given double value.
    
    Parameters:
    
    value - the value to be hashed
    
    Returns:
    
    the hash code
  - hash
```
public static int hash(double[] value)
```
    Returns an integer hash code representing the given double array value.
    
    Parameters:
    
    value - the value to be hashed (may be null)
    
    Returns:
    
    the hash code
    
    Since:
    
    1.2
  - indicator
```
public static byte indicator(byte x)
```
    For a byte value x, this method returns (byte)(+1) if x >= 0 and (byte)(-1) if x < 0.
    
    Parameters:
    
    x - the value, a byte
    
    Returns:
    
    (byte)(+1) or (byte)(-1), depending on the sign of x
  - indicator
```
public static double indicator(double x)
```
    For a double precision value x, this method returns +1.0 if x >= 0 and -1.0 if x < 0. Returns NaN if x is NaN.
    
    Parameters:
    
    x - the value, a double
    
    Returns:
    
    +1.0 or -1.0, depending on the sign of x
  - indicator
```
public static float indicator(float x)
```
    For a float value x, this method returns +1.0F if x >= 0 and -1.0F if x < 0. Returns NaN if x is NaN.
    
    Parameters:
    
    x - the value, a float
    
    Returns:
    
    +1.0F or -1.0F, depending on the sign of x
  - indicator
```
public static int indicator(int x)
```
    For an int value x, this method returns +1 if x >= 0 and -1 if x < 0.
    
    Parameters:
    
    x - the value, an int
    
    Returns:
    
    +1 or -1, depending on the sign of x
  - indicator
```
public static long indicator(long x)
```
    For a long value x, this method returns +1L if x >= 0 and -1L if x < 0.
    
    Parameters:
    
    x - the value, a long
    
    Returns:
    
    +1L or -1L, depending on the sign of x
  - indicator
```
public static short indicator(short x)
```
    For a short value x, this method returns (short)(+1) if x >= 0 and (short)(-1) if x < 0.
    
    Parameters:
    
    x - the value, a short
    
    Returns:
    
    (short)(+1) or (short)(-1), depending on the sign of x
  - lcm
```
public static int lcm(int a,
                      int b)
```
    Returns the least common multiple between two integer values.
    
    Parameters:
    
    a - the first integer value.
    
    b - the second integer value.
    
    Returns:
    
    the least common multiple between a and b.
    
    Throws:
    
    MathException - if the lcm is too large to store as an int
    
    Since:
    
    1.1
  - log
```
public static double log(double base,
                         double x)
```
    Returns the logarithm for base b of x.
    
    Returns NaN if either argument is negative. If base is 0 and x is positive, 0 is returned. If base is positive and x is 0, Double.NEGATIVE_INFINITY is returned. If both arguments are 0, the result is NaN.
    Parameters: base - the base of the logarithm, must be greater than 0 x - argument, must be greater than 0 Returns: the value of the logarithm - the number y such that base^y = x. Since: 1.2
  mulAndCheck public static int mulAndCheck(int x, int y) Multiply two integers, checking for overflow. Parameters: x - a factor y - a factor Returns: the product x*y Throws: MathException - if the result can not be represented as an int Since: 1.1 mulAndCheck public static long mulAndCheck(long a, long b) Multiply two long integers, checking for overflow. Parameters: a - first value b - second value Returns: the product a * b Throws: MathException - if the result can not be represented as an long Since: 1.2 normalizeAngle public static double normalizeAngle(double a, double center) Normalize an angle in a 2&pi wide interval around a center value. This method has three main uses: normalize an angle between 0 and 2π: a = MathUtils.normalizeAngle(a, Math.PI); normalize an angle between -π and +π a = MathUtils.normalizeAngle(a, 0.0); compute the angle between two defining angular positions: angle = MathUtils.normalizeAngle(end, start) - start; Note that due to numerical accuracy and since π cannot be represented exactly, the result interval is closed, it cannot be half-closed as would be more satisfactory in a purely mathematical view. Parameters: a - angle to normalize center - center of the desired 2π interval for the result Returns: a-2kπ with integer k and center-π <= a-2kπ <= center+π Since: 1.2 sign public static byte sign(byte x) Returns the sign for byte value x. For a byte value x, this method returns (byte)(+1) if x > 0, (byte)(0) if x = 0, and (byte)(-1) if x < 0. Parameters: x - the value, a byte Returns: (byte)(+1), (byte)(0), or (byte)(-1), depending on the sign of x sign public static double sign(double x) Returns the sign for double precision x. For a double value x, this method returns +1.0 if x > 0, 0.0 if x = 0.0, and -1.0 if x < 0. Returns NaN if x is NaN. Parameters: x - the value, a double Returns: +1.0, 0.0, or -1.0, depending on the sign of x sign public static float sign(float x) Returns the sign for float value x. For a float value x, this method returns +1.0F if x > 0, 0.0F if x = 0.0F, and -1.0F if x < 0. Returns NaN if x is NaN. Parameters: x - the value, a float Returns: +1.0F, 0.0F, or -1.0F, depending on the sign of x sign public static int sign(int x) Returns the sign for int value x. For an int value x, this method returns +1 if x > 0, 0 if x = 0, and -1 if x < 0. Parameters: x - the value, an int Returns: +1, 0, or -1, depending on the sign of x sign public static long sign(long x) Returns the sign for long value x. For a long value x, this method returns +1L if x > 0, 0L if x = 0, and -1L if x < 0. Parameters: x - the value, a long Returns: +1L, 0L, or -1L, depending on the sign of x sign public static short sign(short x) Returns the sign for short value x. For a short value x, this method returns (short)(+1) if x > 0, (short)(0) if x = 0, and (short)(-1) if x < 0. Parameters: x - the value, a short Returns: (short)(+1), (short)(0), or (short)(-1), depending on the sign of x sinh public static double sinh(double x) Returns the hyperbolic sine of x. Parameters: x - double value for which to find the hyperbolic sine Returns: hyperbolic sine of x subAndCheck public static int subAndCheck(int x, int y) Subtract two integers, checking for overflow. Parameters: x - the minuend y - the subtrahend Returns: the difference x-y Throws: MathException - if the result can not be represented as an int Since: 1.1 subAndCheck public static long subAndCheck(long a, long b) Subtract two long integers, checking for overflow. Parameters: a - first value b - second value Returns: the difference a-b Throws: MathException - if the result can not be represented as an long Since: 1.2

Class MathUtils

Method Summary

Methods inherited from class java.lang.Object

Method Detail

addAndCheck

addAndCheck

binomialCoefficient

binomialCoefficientDouble

binomialCoefficientLog

cosh

equals

equals

factorial

factorialDouble

factorialLog

gcd

hash

hash

indicator

indicator

indicator

indicator

indicator

indicator

lcm

log

mulAndCheck

mulAndCheck

normalizeAngle

sign

sign

sign

sign

sign

sign

sinh

subAndCheck

subAndCheck